Optical element and device for providing uniform irradiance of a surface

Abstract

An optical element uniformly distributes radiant energy on a target surface, such as for discharging an area of a photoreceptor in a xerographic printer, or for applying infrared energy to dry an ink-jet image. A cylinder lens collimates light beams from a light source and directs the collimated light beams to a preselected area on the target surface. First and second refractive portions, each attached to and extending parallel to the cylinder lens, totally internally reflect light beams from the light source and direct the light beams reflected therein to the target surface.

We claim: 
     
       1. An optical element adapted to be interposed between a light source and a target surface, comprising: a meniscus cylinder lens adapted to collimate light beams from the light source and direct the collimated light beams to a preselected area on the target surface; and   first and second reflective portions, each reflective portion attached to and extending parallel to the mensicus cylinder lens, each reflective portion adapted to totally internally reflect light beams from the light source and direct the light beams reflected therein to the preselected area on the target surface, whereby the reflected light beams from the reflective portions are not parallel to the collimated light beams from the menisicus cylinder lens.   
     
     
       2. The optical element of claim 1, each reflective portion further defining an exit surface, each exit surface adapted to direct the light beams reflected in the reflective portion to the preselected area on the target surface. 
     
     
       3. The optical element of claim 1, further comprising a channel defined therein between the first and second reflective portions. 
     
     
       4. An apparatus for irradiating a target surface, comprising: a plurality of light-emitting elements acting as point light sources, arranged in a linear array;   a meniscus cylinder lens adapted to collimate light beams from the light elements and direct the collimated light beams to a preselected area on the target surface; and   first and second reflective portions, each reflective portion attached to and extending parallel to the meniscus cylinder lens, each reflective portion adapted to totally internally reflect light beams from the light sources and direct the light beams reflected therein to the preselected area on the target surface, whereby the reflected light beams from the reflective portions are not parallel to the collimated light beams from the menisicus cylinder lens.   
     
     
       5. The apparatus of claim 4, each reflective portion further defining an exit surface, each exit surface adapted to direct the light beams reflected in the reflective portion to the preselected area on the target surface. 
     
     
       6. The apparatus of claim 4, wherein light beams emitted from each light source between 0° and at least 45° relative to a reference surface, the reference surface passing through the plurality of light sources, are totally internally reflected in a reflective portion. 
     
     
       7. The apparatus of claim 6, wherein at least a portion of light beams emitted from each light source between 90° and 45° relative to the reference surface are collimated by the meniscus cylinder lens.